Survival of polymeric microstructures subjected to interrogatory touch

Area of Science:

• Materials Science and Engineering
• Tribology
• Surface Engineering

Background:

• Polymeric microrelief structures offer diverse applications, including wettability control, bio-inspired adhesion, antifouling, and tactile feedback.
• Understanding the mechanical response of these microstructures to external forces, such as human touch, is crucial for their practical implementation.

Purpose of the Study:

• To investigate the damage mechanisms in micropillar arrays subjected to sliding contact with a human finger cast.
• To determine how micropillar parameters (modulus, spacing, diameter, aspect ratio) influence array survivability and damage modes.

Main Methods:

• Experimental testing of polymeric micropillar arrays with varying geometric and material properties against a silicone finger cast.
• Analysis of damage types, including adhesive failure and material transfer (ploughing).
• Development of a quasi-static mechanics model to estimate forces during micropillar deflection.

Main Results:

• Micropillar aspect ratio is the dominant factor in survivability, influencing bending stiffness.
• Larger pillar diameters reduce susceptibility to breakage and collapse.
• Pillar spacing dictates the type of adhesive failure observed.
• Elastic modulus significantly impacts survivability, with more flexible polymers exhibiting elastic recovery and higher pristine survivability.

Conclusions:

• The study identifies key design parameters for robust micropillar arrays intended for tactile interaction.
• Aspect ratio, diameter, and spacing are critical for preventing damage and ensuring array longevity.
• Material's elastic properties, particularly recovery, play a vital role in the performance of microstructured surfaces under load.